Contact assemblies, methods for making contact assemblies, and plating machines with contact assemblies for plating microelectronic workpieces

ABSTRACT

Contact assemblies, electroplating machines with contact assemblies, and methods for making contact assemblies that are used in the fabrication of microelectronic workpieces. The contact assemblies can be wet-contact assemblies or dry-contact assemblies. A contact assembly for use in an electroplating system can comprise a support member and a contact system coupled to the support member. The support member, for example, can be a ring or another structure that has an inner wall defining an opening configured to allow the workpiece to move through the support member along an access path. In one embodiment, the support member is a conductive ring having a plurality of posts depending from the ring that are spaced apart from one another by gaps. The contact system can be coupled to the posts of the support member. The contact system can have a plurality of contact members projecting inwardly into the opening relative to the support member and transversely with respect to the access path. The contact members can comprise electrically conductive biasing elements, such as fingers, that have a contact site and a dielectric coating covering at least a portion of the biasing elements. The contact members can also have a raised feature configured to engage the seed-layer on the workpiece for conducting the current to the seed-layer.

RELATED APPLICATIONS

[0001] The present application is a continuation-in-part and claimspriority from the following applications: (a) U.S. patent applicationSer. No. 09/113,723 filed Jul. 10, 1998; (b) U.S. Patent Application No.60/111,232 filed Dec. 7, 1998; (c) U.S. Patent Application No.60/119,668 filed Feb. 11, 1999; and (d) PCT Patent Application No.PCT/US99/15847 filed Jul. 12, 1999. All of the foregoing applicationsare herein incorporated by reference in their entirety.

BACKGROUND

[0002] Processors, memory devices, field-emission-displays, read/rightheads and other microelectronic devices generally have integratedcircuits with microelectronic components. A large number of individualmicroelectronic devices are generally formed on a semiconductor wafer, aglass substrate, or another type microelectronic workpiece. In a typicalfabrication process, one or more layers of metal are formed on theworkpieces at various stages of fabricating the microelectronic devicesto provide material for constructing interconnects between variouscomponents.

[0003] The metal layers can be applied to the workpieces using severaltechniques, such as chemical vapor deposition (CVD), physical vapordeposition (PVD), plasma-enhanced deposition processes, electroplating,and electroless plating. The particular technique for applying a metalto a workpiece is a function of the particular type of metal, thestructure that is being formed on the workpiece, and several otherprocessing parameters. For example, CVD and PVD techniques are oftenused to deposit aluminum, nickel, tungsten, solder, platinum and othermetals. Electroplating and electroless plating techniques can be useddeposit copper, solder, permalloy, gold, silver, platinum and othermetals. Electroplating and electroless plating can be used to formblanket layers and patterned layers. In recent years, processes forplating copper have become increasingly important in fabricatingmicroelectronic devices because copper interconnects provide severaladvantages compared to aluminum and tungsten for high-performancemicroelectronic devices.

[0004] Electroplating is typically performed by forming a thinseed-layer of metal on a front surface of a microelectronic workpiece,and then using the seed-layer as a cathode to plate a metal layer ontothe workpiece. The seed-layer can be formed using PVD or CVD processes.The seed-layer is generally formed on a topographical surface havingvias, trenches, and/or other features, and the seed-layer is generallyapproximately 1000 angstroms thick. The metal layer is then plated ontothe seed-layer using an electroplating technique to a thickness ofapproximately 6,000 to 15,000 angstroms. As the size of interconnectsand other microelectronic components decrease, it is becomingincreasingly important that a plated metal layer (a) has a uniformthickness across the workpiece, (b) completely fills the vias/trenches,and (c) has an adequate grain size.

[0005] Electroplating machines for use in manufacturing microelectronicdevices often have a number of single-wafer electroplating chambers. Atypical chamber includes a container for holding an electroplatingsolution, an anode in the container to contact the electroplatingsolution, and a support mechanism having a contact assembly withelectrical contacts that engage the seed-layer. The electrical contactsare coupled to a power supply to apply a voltage to the seed-layer. Inoperation, the front surface of the workpiece is immersed in theelectroplating solution so that the anode and the seed-layer establishan electrical field that causes metal in a diffusion layer at the frontsurface of the workpiece to plate onto the seed-layer.

[0006] The structure of the contact assembly can significantly influencethe uniformity of the plated metal layer because the plating rate acrossthe surface of the microelectronic workpiece is influenced by thedistribution of the current (the “current density”) across theseed-layer. One factor that affects the current density is thedistribution of the electrical contacts around the perimeter of theworkpiece. In general, a large number of discrete electrical contactsshould contact the seed-layer proximate to the perimeter of theworkpiece to provide a uniform distribution of current around theperimeter of the workpiece. Another factor that affects the currentdensity is the formation of oxides on the seed-layer. Oxides aregenerally resistive, and thus oxides reduce the efficacy of theelectrical connection between the contacts and the seed-layer. Stillother factors that can influence the current density are (a) galvanicetching between the contacts and the seed-layer, (b) plating on thecontacts during a plating cycle, (c) gas bubbles on the seed-layer, and(d) other aspects of electroplating that affect the quality of theconnection between the contacts and the seed-layer or the fluid dynamicsat the surface of the workpiece. The design of the contact assemblyshould address these factors to consistently provide a uniform currentdensity across the workpiece.

[0007] One type of contact assembly is a “dry-contact” assembly having aplurality of electrical contacts that are sealed from the electroplatingsolution. For example, U.S. Pat. No. 5,227,041 issued to Brogden et al.discloses a dry contact electroplating structure having a base memberfor immersion into an electroplating solution, a seal ring positionedadjacent to an aperture in the base member, a plurality of contactsarranged in a circle around the seal ring, and a lid that attaches tothe base member. In operation, a workpiece is placed in the base memberso that the front face of the workpiece engages the contacts and theseal ring. When the front face of the workpiece is immersed in theelectroplating solution, the seal ring prevents the electroplatingsolution from contacting the contacts inside the base member. Onemanufacturing concern of dry-contact assemblies is that galvanic etchingoccurs between the contacts and the seed-layer when an electrolytesolution gets into the dry contact area. Galvanic etching removes theseed-layer at the interface of the contacts, which can cause anon-uniform current distribution around the perimeter of the workpiece.Therefore, even though dry-contact assemblies keep the contacts clean,they may produce non-uniform metal layers on the workpieces.

[0008] Another type of contact assembly is a “wet-contact” assemblyhaving a plurality of electrical contacts that are exposed to theelectroplating solution during a plating cycle. Because the contacts areexposed to the electroplating solution during a plating cycle, the metalin the electroplating solution also plates onto the contacts. Thecontacts, however, may plate at different rates such that some contactscan have a greater surface area of conductive material contacting theseed-layer. The in-situ plating of contacts can accordingly reduce theuniformity of the metal layer on the workpiece. Additionally,wet-contact assemblies must be periodically “de-plated” to remove themetal that plates onto the contacts during a plating cycle. Therefore,it would be desirable to develop a wet-contact assembly that eliminatesor reduces the processing concerns associated with exposing the contactsto the electroplating solution.

SUMMARY

[0009] The present invention is generally directed toward contactassemblies, electroplating machines with contact assemblies, and methodsfor making contact assemblies that are used in the fabrication ofmicroelectronic workpieces. The contact assemblies can be wet-contactassemblies or dry-contact assemblies. In one aspect of the invention, acontact assembly for use in an electroplating system comprises a supportmember and a contact system coupled to the support member. The supportmember, for example, can be a ring or another structure that has aninner wall defining an opening configured to allow the workpiece to movethrough the support member along an access path. In one embodiment, thesupport member is a conductive ring having a plurality of posts thatdepend from the ring and are spaced apart from one another by gaps.

[0010] The contact system can be coupled to the posts of the supportmember. The contact system can have a plurality of contact membersprojecting inwardly into the opening relative to the support member andtransversely with respect to the access path. The contact members cancomprise electrically conductive biasing elements, such as fingers, thathave a contact site and a dielectric coating configured to expose thecontact sites. In one embodiment, the contact system further comprises aconductive mounting section attached directly to the posts to defineflow paths through the gaps. The contact members can project inwardlyfrom the mounting section along a radius of the opening or at an angleto a radius of the opening to define cantilevered spring elements thatcan support the workpiece. The contact members can also have a raisedfeature configured to engage the seed-layer on the workpiece.

[0011] In operation, a workpiece is loaded into the contact assembly byinserting the workpiece through the opening of the support member untilthe front face of the workpiece engages the contact sites on the contactmembers. Because the contact members can be biasing elements that flex,the contact members flex downwardly and transversely relative to theaccess path so that the contact sites adequately engage the seed-layeron the workpiece even though the face of the workpiece may have vias,trenches and other topographical features. The face of the workpiece andthe contact members can then be immersed in an electroplating solutionwhile the contact assembly rotates. Because the contact members areexposed to the electroplating solution, the metal in the solutioncontinuously plates the interface between the contact sites and theseed-layer. The plating of the contact/seed-layer interface mitigatesthe galvanic etching of seed-layer. Additionally, several embodiments ofcontact members have a dielectric coating with stepped edges adjacent tothe contact site that inhibit the metal from plating over the dielectriclayer. The stepped edges accordingly reduce the problems associated withde-plating the contacts. Also, in embodiments that have a raised featureon the contact members, the electroplating solution can flow morereadily between the contact members and the workpiece to reduce platingon the contact members. Therefore, several embodiments of contactassemblies are expected to enhance the quality and throughput ofelectroplating microelectronic workpieces.

BRIEF DESCRIPTION THE DRAWINGS

[0012]FIG. 1 is an isometric view with a cut-away portion of anelectroplating machine having a contact assembly in accordance with oneembodiment of the invention.

[0013]FIG. 2 is a cross-sectional view of an electroplating chamberhaving a contact assembly for use in an electroplating machine inaccordance with an embodiment of the invention.

[0014]FIG. 3 is an isometric view illustrating a portion of a contactassembly for use in an electroplating machine in accordance with anembodiment of the invention.

[0015]FIG. 4 is an isometric view illustrating a cross-section of acontact assembly for use in an electroplating machine in accordance withan embodiment of the invention.

[0016]FIG. 5 is a cross-sectional view of a portion of the contactassembly of FIG. 4 illustrating a contact member in accordance with anembodiment of the invention in greater detail.

[0017]FIG. 6 is an isometric view illustrating a portion of a contactassembly for use in an electroplating machine in accordance with anotherembodiment of the invention.

[0018]FIG. 7 is top plan view of a contact assembly for use in anelectroplating machine in accordance with another embodiment of theinvention.

[0019]FIG. 8 is an isometric view of a contact assembly for use in anelectroplating machine in accordance with another embodiment of theinvention.

[0020]FIG. 9 is a top plan view of a contact system for use in a contactassembly in accordance with an embodiment of the invention.

[0021]FIGS. 10 and 11 are cross-sectional views of contact members forcontact assemblies in accordance with additional embodiments of theinvention.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

[0022] The following description discloses the details and features ofseveral embodiments of contact assemblies, methods for making contactassemblies, and electroplating machines with contact assemblies forelectroplating metal layers onto microelectronic workpieces. It will beappreciated that several of the details set forth below are provided todescribe the foregoing embodiments in a manner sufficient to enable aperson skilled in the art to make and use contact assemblies andelectroplating systems in accordance with embodiments of the invention.Several of the details and advantages described below, however, may notbe necessary to practice embodiments of the invention accordance withthe following claims. For example, many of the embodiments describedbelow are directed toward wet-contact assemblies, but these same devicescan also be used in dry-contact assemblies as shown in PCT ApplicationNo. PCT/US99/15847. Additionally, the invention can also includeadditional embodiments that are within the scope of the claims but arenot described in detail with respect to FIGS. 1-11.

[0023] The operation and features of the contact assemblies are bestunderstood in light of the environment and equipment in which they canbe used to electroplate workpieces. As such, several embodiments ofelectroplating tools and reaction chambers that can be used with thecontact assemblies will be described with reference to FIGS. 1 and 2.The details and features of several embodiments of contact assemblieswill then be described with reference to FIGS. 3-11.

[0024] A. Selected Embodiments of Electroplating Machines and ReactorChambers for Use With Contact Assemblies to Electroplate Metals ontoMicroelectronic Workpieces

[0025]FIG. 1 is a front isometric view of an electroplating machine 100in which contact assemblies in accordance with embodiments of theinvention can be used. The electroplating machine 100 can include acabinet 102, a load/unload mechanism 104 at one end of the cabinet 102,and a plurality of chambers 110 in the cabinet 102. The chambers 110 caninclude electroplating chambers 112, electroless plating chambers 114,and/or rapid thermal annealing chambers 118. The electroplating chambers112 can include a contact assembly (not shown in FIG. 1) to apply anelectrical potential to a seed-layer on the workpiece. Theelectroplating machine 100 can also include a transfer mechanism 120having a rail or track 122 and a plurality of robots 124 that move alongthe track 122. The robots 124 include arms 126 that can carry amicroelectronic workpiece 130 between the chambers 110. In operation,the load/unload mechanism 104 positions a cassette holding a pluralityof workpieces in the cabinet 102, and the transfer mechanism 120 handlesthe individual workpieces 130 inside the cabinet 102. The transfermechanism 120, for example, can initially place the workpiece 130 in anelectroless plating chamber 114 to repair or enhance the seed-layer onthe workpiece. The transfer mechanism 120 can then remove the workpiece130 from the electroless plating chamber 114 and place it in theelectroplating chamber 112 for forming a blanket layer or a patternedlayer on the front face of the workpiece 130. In an alternativeembodiment, the transfer mechanism can be a radial system such as in theEQUINOX® machines manufactured by Semitool, Inc. of Kalispell, Mont.After the electroplating cycle, the transfer mechanism 120 can removethe workpiece 130 from the electroplating chamber 112 and transfer it toanother processing station in the machine 100 (e.g., a standardrinser-dryer, a rinse/etch capsule, an annealing chamber, etc.) or placeit in the cassette.

[0026]FIG. 2 is a partial cross-sectional view of an electroplatingchamber 112 having a contact assembly 200 in accordance with oneembodiment of the invention for supporting and providing an electricalconnection to a front face of the workpiece 130. For the purposes ofbrevity, several components of the electroplating chamber 112 are shownschematically or by line drawings. Many of the particular features ofthe components shown schematically are described more detail in thepatent applications incorporated by reference. The electroplatingchamber 112 can include a bowl 140 configured to contain anelectroplating solution, an anode 150 in the bowl 140, and a headassembly 170 that carries the contact assembly 200. The head assembly170 is movable with respect to the bowl 140 to position the workpiece130 in the plating solution (not shown). In the embodiment shown in FIG.2, the head assembly 170 is shown in a partially inserted position inwhich the contact assembly 200 and the workpiece 130 are at a slightangle. When the head assembly 170 is fully inserted into the bowl 140, abeveled surface 172 of the head assembly 170 is superimposed over acorresponding beveled surface 142 of the bowl 140, and the contactassembly 200 holds the workpiece 130 in a desired position relative tothe plating solution.

[0027] The bowl 140 can include a cup 144 having an overflow wier 146.The anode 150 is positioned in the cup 144, and the anode 150 can beattached to an anode support assembly 152. In one embodiment, the anodesupport assembly 152 has a channel 154 through which the electroplatingsolution flows and is discharged into the cup 144. The anode supportassembly 152 can be electrically conductive, or it can include aconductor to electrically couple the anode 150 to a power supply. Inoperation, a flow of plating solution (identified schematically byarrows “S”) passes through the anode support assembly 152 and isdischarged into the cup 144 underneath the anode 150. The platingsolution flow S continues around the anode 150, over the wier 146, andinto a lower portion of the bowl 140. As the plating solution flow Spasses over the wier 146, it forms a meniscus at the top of the cup 144.The plating solution flow S can then pass out of the bowl 140 where itis filtered and reconditioned so that the plating solution can bere-circulated through the cup 144. Suitable embodiments of bowls 140,cups 144, anodes 150 and anode support assemblies 152 are described inPCT Application Nos. PCT/US99/15430 and PCT/US00/10210, which are hereinincorporated by reference.

[0028] The head assembly 170 can further include a motor 174 and a rotor180 that carries the contact assembly 200. The motor 174 is coupled tothe rotor 180 to rotate the contact assembly 200 and the workpiece 130during a plating cycle (Arrow R). The rotor 180 can include a movablebacking plate 182 and a seal 184. The backing plate 182 can movetransverse to the workpiece 130 (Arrow T) between a first position inwhich the backing plate 182 engages the back side of the workpiece 130(shown in solid lines in FIG. 2) and a second position in which it isspaced apart from the back side of the workpiece 130 (shown in brokenlines in FIG. 2). In this embodiment, the contact assembly 200 iscoupled to the rotor 180 by a plurality of shafts 202 that are receivedin quick-release mechanisms 204. The shafts 202 can be rigid, conductivemembers that electrically couple the contact assembly 200 to anelectrical potential so that the seed-layer on the workpiece 130 is acathode.

[0029] In operation, the head assembly 170 can be initially raised abovethe bowl 140 and rotated about a relatively horizontal axis to positionthe contact assembly 200 to face upward away from the bowl 140. Thebacking plate 182 is moved to the second position in which it is spacedapart from the contact assembly 200 to load the workpiece 130 into thehead assembly 170. The robot 124 (FIG. 1) inserts the workpiece 130face-up into the contact assembly 200, and then the backing plate 182moves to the first position in which it presses the workpiece 130against the contact assembly 200. The head assembly 170 then rotatesabout the horizontal axis to position the contact assembly 200 facedownward and lowers the loaded workpiece 130 and a portion of thecontact assembly 200 into the plating solution proximate to the overflowwier 146. The motor 174 rotates the rotor 180 about a relativelyvertical axis to move the workpiece 130 in the plating solution duringthe plating cycle. After the plating cycle is complete, the headassembly 170 removes the workpiece 130 from the plating solution so thatit can be rinsed and/or transferred to another processing chamber ormachine. In an alternative embodiment, the head assembly does not rotateabout the horizontal axis to position the contact assembly 200 face-upduring a load/unload sequence such that the workpiece is loaded into thecontact assembly face-down toward the bowl 140.

[0030] The foregoing description of the electroplating machine 100 andthe electroplating chamber 112 provides examples of the types of devicesin which contact assemblies in accordance with embodiments of theinvention can be used to plate metal layers onto microelectronicworkpieces. It will be appreciated that the contact assembly 200, andother embodiments of contact assemblies described in more detail below,can be used with other electroplating machines and reaction chambers.

[0031] B. Selected Embodiments of Contact Assemblies for ElectroplatingMicroelectronic Workpieces

[0032] FIGS. 3-11 illustrate several embodiment contact assemblies thatcan be used in the electroplating chamber 112 of the electroplatingmachine 100. The structures and operation of the contact assembliesshown in FIGS. 3-11 are generally described with reference towet-contact assemblies. It will be appreciated, however, that they canalso be configured to be dry-contact assemblies. Therefore, the basicstructure is applicable to both wet-contact and dry-contactelectroplating applications.

[0033]FIG. 3 is an isometric view showing the features of an embodimentof the contact assembly 200 in greater detail. In this embodiment, thecontact assembly 200 has a support member 210 and a contact system 250attached to the support member 210. The shafts 202 can be connected tothe support member 210 to attach the contact assembly 200 to the headassembly 170 (FIG. 2). The support member 210 can have a circular shape,a shape with one or more straight-edge sections, or any other suitableshape corresponding to the shape of the workpiece. The embodiment of thesupport member 210 shown in FIG. 2 is a ring having an inner wall 212defining an opening that is configured to allow the workpiece 130 (FIG.2) to move through the support member 210 along an access path “P.” Thesupport member 210 can be formed from a conductive material, such astitanium, stainless-steel, or another suitable metal. In an alternativeembodiment, the support member 210 can be formed from a dielectricmaterial and further include conductive lines extending through thedielectric material. In this embodiment, the support member 210 includesa plurality of posts 214 and workpiece guides 216. The posts 214 projectdownwardly from the main portion of the conductive ring, and the posts214 can have squared corners or rounded corners. The posts 214 can alsohave rectilinear or circular cross-sections, and in one embodiment theposts are approximately 0.10-0.40 inch wide. The posts 214 are spacedapart from one another by gaps 218 that provide passageways for gasbubbles and electroplating solution to pass through the support member210 during a plating cycle. In one particular embodiment, the gaps areapproximately 0.10-0.30 inch high and 0.10-0.25 inch wide. The workpieceguides 216 can be positioned around the interior of the support member210 at selected radial increments, such as 15°, 30°, 60°, etc. Theworkpiece guides 216 can have a tapered surface 219 that slopes into theopening for guiding the workpiece 130 onto the contact system 250. Theworkpiece guides 216 can include other embodiments or be arranged aroundthe interior of the support member 210 in different patterns, and theposts 214 and the gaps 218 can have different sizes and shapes thanthose set forth above.

[0034] The contact system 250 can comprise a conductive mounting section252 and a plurality of contact members 254 projecting from the mountingsection 252 into the opening defined by the support member 210. Themounting section 252, for example, can be a ring that is connected tothe posts 214 of the support member 210 by spot welds, screws, or othersuitable techniques. The mounting section 252 can alternatively be asegment, such as an arcuate segment of a ring, and a plurality ofseparate segments can be attached to the posts 214 of the support member210. The mounting section 252 and the contact members 254 can be formedfrom an electrically conductive material and/or have a suitableelectrically conductive coating. In one embodiment, the mounting section252 and a contact members 254 are made from a sheet of metal, such astitanium, stainless-steel, or another suitably conductive material thatcan flex under the loads generated by the backing plate 182 as itpresses the workpiece 130 against the contact members 254.

[0035] The contact members 254 can be conductive biasing elements thatproject inwardly into the opening defined by the inner wall 212 of thesupport member 210 and transversely with respect to the access path P.In one embodiment, the contact members 254 are cantilevered springelements. The contact members 254 can be integral with the mountingsection 252, or they can be individual fingers that are attached to themounting section 252 by spot welds or other suitable fasteners. In thisembodiment, the contact members 254 are cantilevered spring elements orfingers that project inwardly along a radius of the support member 210.

[0036]FIG. 4 is a partial isometric view that illustrates an embodimentof the support member 210, the mounting section 252, and the contactmembers 254 in greater detail. The posts 214 of the support member 210can have an angled lower surface that projects upwardly with respect tothe access path P. Additionally, the mounting section 252 and thecontact members 254 can be formed to have a conical shape that anglesupwardly such that the contact members 254 also project upwardly withrespect to the access path P. The upward angle is approximately 5°-15°,and more specifically can be approximately 8°. In an alternativeembodiment, the support members 254 can extend approximately normal tothe access path P. In operation, the backing member 182 (FIG. 2) drivesthe workpiece 130 downward along the access path P causing the contactmembers 254 to flex downwardly and slide transversely across the surfaceof the workpiece 130. The downward flexing of the contact members 254allows the contact members 254 to conform to a topographical surface ofthe workpiece 130, and the sliding of the contact members 254 removesoxides that may have grown on the seed-layer.

[0037]FIG. 5 is a cross-sectional view illustrating a portion of anembodiment of the contact assembly 200 that is particularly well-suitedfor use as a wet-contact assembly in which the contact system 250 and aportion of the support member 210 are submerged in a plating solution.In this embodiment, the mounting section 252 and the contact members 254are stamped or otherwise formed from a sheet of titanium or anothersuitable conductive material so that the mounting section 252 and thecontact members 254 are integral with one another. The mounting section252 and the contact members 254 can be coated with a layer of aconductive contact material 256. One suitable metal for the contactlayer 256 is platinum, but other metals that interact with the platingsolution and the seed-layer in a desired manner can be used. The supportmember 210 and the contact system 250 can then be coated with adielectric coating 257. The dielectric coating 257 is generally selectedaccording to (a) the compatibility with the plating solution, (b)adhesion to the metal of the contact system 250, and (c) ability toeffectively coat the contact system 250. Suitable materials that can beused for the dielectric coating 257 include (a) an 8840 primer and aTeflon dielectric exterior coating manufactured by DuPont® (“DuPont”);(b) an 8840 green coating manufactured by DuPont; (c) a 954-100 epoxybased coating manufactured by DuPont; (d) a 954-101 epoxy based coatingmanufactured by DuPont; (e) HALAR® coatings under the name Dycore® 404;(f) KYNAR® coatings under the identification Dycore® 202 either with orwithout a primer of Dycore 204; (g) HALAR® heavy coatings; (h)FLUOROLON® 109 distributed by Southwest Impreglon® Sales, Inc. of Texas;(i) Impreglon 216® or Impreglon 872® distributed by Southwest Impreglon®Sales, Inc.; and (j) other epoxy based coatings, thermoplasticcopolymers, or fluorocarbon resins. It will be appreciated that othermaterials can be used for the dielectric coating 257, and thus theforegoing materials provide examples that are not intended to limit theclaims.

[0038] The contact members 254 can also have an aperture 258 formed inthe dielectric coating 257 at a contact site 259 to expose a portion ofthe contact layer 256. The aperture 258 can be formed by laser ablatingtechniques that consume the dielectric coating 257 to form stepped edgesat the aperture 258. Laser ablating techniques can be closely controlledso that the dielectric coating 257 can be removed from the contact layer256 without damaging or impairing the performance of the contact layer256. For example, the energy and/or wavelength of the laser can beselected so that it consumes the dielectric coating 257 withoutaffecting the contact layer 256. Additionally, the residence time thatthe laser impinges the dielectric coating 257 can be controlled so thatthe laser is moved before it consumes the contact layer 256. Theaperture 258 can alternatively be formed using machining techniques. Ineither case, the dielectric coating 257 does not cover the contact site259 so that the contact member 254 can provide an electrical potentialto the seed-layer on the workpiece 130.

[0039]FIGS. 2 and 3 illustrate the operation and advantages of severalembodiments of the contact assembly 200. Referring to FIG. 2, when thehead assembly 170 rotates the workpiece 130, the plating solution at thefront face of the workpiece 130 is driven radially outwardly toward thesupport member 210. Referring to FIG. 3, the plating solution and anygas bubbles at the surface of the workpiece 130 pass through the gaps218 of the support member 210. An electrical potential is also appliedto seed-layer on the workpiece via the contact system 250 to establish acurrent field between the anode 150 and the seed-layer. The currentbetween the anode 150 and the seed-layer causes the metal in the platingsolution to plate onto the seed-layer and portions of the contactmembers 254 because the contact members 254 are also exposed to theplating solution. After an adequate layer of metal has been plated ontothe workpiece 130, the head assembly 170 raises the contact assembly 200to an intermediate elevation at which a rinsing solution is applied tothe workpiece 130 as it continues to rotate. The head assembly 170 isthen raised to clear the upper lip of the bowl 140, and the workpiece130 is removed from the contact assembly 200. The head assembly 170 canthen be re-lowered to submerge the contact assembly 200 in the platingsolution for de-plating the contact members 254 by switching thepotential applied to the contact members 254 so that the contact members254 are the anode and applying an opposite potential to a ring cathode270 in the bowl 140.

[0040] When the contact assembly 200 is used in a wet-contactenvironment, several embodiments of the contact assembly 200 reducegalvanic etching of the seed-layer at the interface between the contactmembers and the seed-layer compared to dry-contact assemblies. Becausethe contact assembly 200 has contact members 254 coated with adielectric material, it can be a “wet-contact” assembly in which thecontact members 254 are exposed to the plating solution. The etchingcaused by the galvanic effect between the seed-layer and the contactmembers 254 before being immersed in the plating solution does not occurafter the contact assembly 200 is placed in the plating solution.Therefore, several embodiments of the contact assembly 200 are expectedto provide a uniform current distribution around the perimeter of theworkpiece throughout a plating cycle to enhance the uniformity of theplated layer.

[0041] Several embodiments of the contact assembly 200 also provide alarge number of contacts that uniformly engage the perimeter of theworkpiece. Because the contact members 254 flex downwardly as theworkpiece is loaded into the contact assembly 200, the contact members254 can compensate for topographical variances across the surface of theworkpiece to provide a uniform pressure against the various contactpoints on seed-layer. Additionally, the large number of individualcontact members 254 enhance the uniformity of the electrical potentialaround the perimeter of the workpiece. Therefore, several embodiments ofthe contact assembly 200 are expected to further enhance the uniformityof the plated layer by providing a large number of contact members 254that can adapt to different topographical features on the workpiece.

[0042] Several embodiments of the contact assembly 200 used forwet-contact applications reduce non-uniformities caused by bubbles inthe plating solution. One problem of electroplating is that bubbles canform on the anode 150 (FIG. 2) and rise through the plating solution tothe face of the workpiece 130. Air can also be trapped on the face ofthe workpiece 130 as it is lowered into the plating solution. As theworkpiece 130 rotates through the plating solution, the bubbles aredriven radially outward toward the perimeter of the workpiece. If thebubbles are trapped at the perimeter of the workpiece, they can preventthe plating solution from contacting the workpiece in a manner thatcauses non-uniform plating. The contact assembly 200 mitigates thisproblem because any such bubbles can flow through the gaps 218 betweenthe posts 214 of the support member 210. Therefore, several embodimentsof the contact assembly 200 are expected to reduce non-uniformitiescaused by bubbles in the plating solution.

[0043] Selected embodiments of the contact assembly 200 also enhance theuniformity of the electrical interface between the contact members 254and the seed-layer by mechanically impairing the metal from plating overthe dielectric coating 257 adjacent to the contact sites 259. Anotherproblem of using a conventional wet-contact assembly is that the metalcan plate over the dielectric coating during the plating cycle. Themetal that plates over the dielectric coating may not be completelyremoved during a de-plating cycle, or it can increase the duration ofthe de-plating cycle causing a reduction in throughput of theelectroplating machine. In embodiments of the contact assembly 200 inwhich the dielectric coating 257 is removed from the contact sites 259using laser ablating techniques, the stepped edge of the aperture 258creates a step-height that inhibits the metal from plating onto thedielectric coating 257 adjacent to the aperture 258. Laser ablatedapertures 258 accordingly eliminate or at least reduce the amount ofmetal that must be removed by the de-plating process. Therefore, certainembodiments of the contact assembly 200 are expected to enhance theefficacy of de-plating processes to provide a more consistent electricalinterface between the contact members 254 and the seed-layer.

[0044]FIG. 6 is a partial isometric view of a contact assembly 300 inaccordance with another embodiment of the invention. The contactassembly 300 can include a support member 310 and a contact system 350comprising a plurality of individual, separate contact members 354. Thesupport member 310 can be substantially similar to the support member210 described above. The support member 310 can accordingly have aninner wall 312 defining an opening configured to receive the workpiece130 and a plurality of posts 314 that are spaced apart from one anotherby gaps 318. The individual contact members 354 can be similar to thecontact members 254 described above with reference to FIGS. 4 and 5,except that the individual contact members 354 have individual mountingsections 356 attached to the posts 314 by spot welds or other suitablefasteners. The contact system 350 accordingly does not include amounting section spanning between the posts 314. The support member 310and the contact members 354 can be coated with the same coatingsdescribed above with reference to FIGS. 4 and 5. The contact assembly300 operates in a manner that is similar to the contact assembly 200described above, and several embodiments of the contact assembly 300 mayalso provide similar advantages as the contact assembly 200.

[0045]FIG. 7 is a top plan view of a contact assembly 400 in accordancewith another embodiment of the invention. The contact assembly 400 caninclude a support member 410 and a contact system 450 attached to thesupport member 410. The support member 410 can be a conductive ringhaving a plurality of downwardly depending posts (not shown in FIG. 7)that are separated from one another by gaps similar to the posts 214shown in FIG. 3.

[0046] The support member 410 also has a plurality of guides 416 thatare arranged in a first guide pair 420, a second guide pair 422, and athird guide pair 424. In this embodiment, the guide pairs 420, 422, and424 are spaced apart from one another by approximately 120° around theinterior of the support member 410. The first guide pair 420 can bespaced 60° apart from one of the contact shafts 202, and the secondguide pair 422 can be spaced 60° apart from the other contact shaft 202on the same side of the support member 410. The third guide pair 424 canbe spaced equally between the contact shafts 202 on the other side ofthe support member 410. This spacing of the guide pairs inhibits theplating solution from wicking up the guides 416 and onto the back sideof the workpiece as the head assembly 170 (FIG. 2) lowers one side ofthe contact assembly 400 into the plating solution at an angle relativeto the overflow wier 146 (see the contact assembly 200 shown in FIG. 2).For example, if the contact assembly 400 shown in FIG. 7 is attached tothe head assembly 170 shown in FIG. 2 so that a first region 430 of thecontact assembly 400 is lowered into the plating solution and then asecond region 432 is the final portion of the contact assembly 400lowered into the solution, then the guides 416 are spaced apart from thefirst region 430 so that the plating solution does not wick up betweenthe guides 416 and the workpiece. If the guides 416 were located at thefirst region 430, then the plating solution may wick up the guides andonto the backside of the workpiece.

[0047] The guides 416 are not limited to the arrangement shown in FIG.7. The guides 416, for example, can be arranged individually or in pairsso that the guides 416 are generally spaced apart from the portion ofthe contact assembly that is (a) initially submerged in the platingsolution and/or (b) submerged to the greatest depth in the platingsolution. Therefore, the contact assembly 400 may have additionalembodiments that inhibit contamination of the backside of the workpiececaused by wicking of the plating solution.

[0048]FIG. 8 is an isometric view of a contact assembly 500 inaccordance with another embodiment of the invention for use in a reactorchamber of a plating machine. The contact assembly 500 can have asupport member 510 and a contact system 550 comprising a plurality ofswept or angled contact members 554. The support member 510 can have aninner wall 512 defining an opening for receiving the workpiece, aplurality of posts 514 spaced apart from one another by gaps 518, and aplurality of guides 516 arranged around the inner wall 512. The posts514 can be substantially the same as the posts 214, and the guides 516can be arranged as set forth above in FIG. 3 or 7. In FIG. 8, morespecifically, the guides 516 are arranged in guide pairs to inhibitwicking of the plating solution. The contact system 550 is attached tothe posts 514 of the support member 510 so that bubbles can flow throughthe gaps 518 in the support member 510.

[0049]FIG. 9 is a top plan view illustrating a portion of an embodimentof the contact system 550 in greater detail. Referring to FIGS. 8 and 9together, the contact system 550 can further comprise a mounting section552, such as an arcuate ring, a segment of an arcuate ring, or anotherstructure for mounting the contact members 554 to the support structure510. The contact members 554 can project from the mounting section 552inwardly into the opening of the support member 510 at an angle relativeto a radius of the support member 510. Additionally, the contact members554 can project upwardly in a manner similar to the contact member 254shown in FIG. 4. The support member 510 and the contact system 550 canbe made from and coated with the materials set forth above with respectto the contact assembly 200. As such, the contact members 554 can have acontact site 559 for contacting the seed-layer on the workpiece.

[0050] The contact assembly 500 is expected to provide a good electricalconnection between the contact members 554 and the seed-layer on theworkpiece. One aspect of plating microelectronic workpieces is that thereal estate on the front face of the workpiece should be used to formfeatures, and thus the contact members 554 should not extend too farinward from the perimeter of the workpiece. It is also generallydesirable that the contact members have a relatively long lever arm sothat they flex easily as the workpiece presses against them. The contactsystem 550 provides a solution to increase the length of the lever armof the contact member 554 without extending further inwardly beyond theperimeter of the workpiece by angling the contact member 554 relative todiametric lines of the support member 510. Therefore, the contactmembers 554 have desirable flexural qualities without affecting theavailable real estate on the workpiece for fabricating devices.

[0051] The contact assembly 500 is also expected to provide a desirableflow of the plating solution at the perimeter of the workpiece. Inoperation, the workpiece is rotated in a direction R so that the inwardedges 560 of the contact members 554 drive the plating solution towardthe interior of the workpiece. The swept contact members 554 accordinglydrive the plating solution away from the perimeter, and the sweptcontact members 554 are expected to produce less turbulence at theperimeter than radially projecting contact members. As a result, theswept contact members 554 are expected to provide a desirable flow ofthe plating solution at the perimeter of the workpiece.

[0052]FIG. 10 is a cross-sectional view of a contact member 754comprising a biasing element 755 having a raised feature 780 at acontact site 760 for contacting the seed-layer of the workpiece. Thebiasing element 755 can be a finger made from titanium or anothersuitable conductive material with desirable structural qualities. Aconductive contact layer 756 can coat the biasing element 755, and adielectric coating 758 can cover the contact layer 756. The contactlayer 756 can be platinum or another suitable metal, and the dielectriccoating 758 can be one of the coatings described above. The dielectriccoating 758 can be removed from the contact site 760 to expose thecontact layer 756 on the raised feature 780 using a laser ablationtechnique. As a result, the dielectric coating 758 can have an aperture759 with a stepped edge to inhibit the metal in the plating solutionfrom plating over the dielectric coating 758 adjacent to the aperture759. In this embodiment, the raised feature 780 is a deformed portion ofthe biasing element 755, and the contact layer is a conformal layer thatis plated onto the biasing element 755.

[0053]FIG. 11 is a cross-sectional view of a contact member 854 having abiasing element 855 with a raised feature 880 at a contact site 860. Thebiasing element 855 can be a finger that is coated with a dielectriclayer 858. In this embodiment, the dielectric layer 858 has an aperture859 at the contact site 860, and the raised feature 880 is a bump ofcontact material deposited at the contact site 860. The raised feature880, for example, can be a platinum bump. The contact members 254, 354and 554 described above can have the structure of the contact members754 or 854 shown in FIGS. 10 and 11.

[0054] Several embodiments of the contact member 754 an 854 are expectedto provide a more consistent, uniform electrical connection between thecontact assembly and the seed-layer in wet-contact plating processes.The raised features on the contact members space the workpiece apartfrom the contact members so that the plating solution can flow moreeasily adjacent to the contact points. The increased flow of the platingsolution reduces the size of the diffusion layer at the contact pointsin a manner that reduces plating onto the contact sites and over thedielectric coating adjacent to the contact sites. Such a reduction inplating at the contact sites should provide a consistent electricalconnection throughout a plating cycle to provide a more uniform currentdistribution around the perimeter of the workpiece. Also, a reduction inplating on the contact members is expected to reduce the time expendedfor de-plating the contact assembly. Thus, contact members with raisedfeatures should increase both the uniformity of the current distributionand the throughput of electroplating processes.

[0055] From the foregoing it will be appreciated that specificembodiments of the invention have been described herein for purposes ofillustration, but that various modifications may be made withoutdeviating from the spirit and scope of the invention.

[0056] Accordingly, the invention is not limited except by the appendedclaims.

The claimed subject matter is:
 1. A contact assembly for use in anelectrochemical deposition system to apply an electrical potential to amicroelectronic workpiece, the contact assembly comprising: a supportmember having an inner wall defining an opening configured to allow theworkpiece to move through the support member along an access path; and acontact system coupled to the support member, the contact system havinga plurality of contact members projecting inwardly into the openingrelative to the support member and transversely with respect to theaccess path, wherein the contact members each have a contact siteconfigured to electrically contact the workpiece and a dielectriccoating around the contact site.
 2. The contact assembly of claim 1wherein the contact members comprise cantilevered spring elementsprojecting upwardly into the opening.
 3. The contact assembly of claim 1wherein the contact members comprise cantilevered spring elementsprojecting upwardly into the opening, and the cantilevered springelements have a raised feature.
 4. The contact assembly of claim 1wherein the contact members comprise cantilevered spring elementsprojecting upwardly into the opening, and the cantilevered springelements have a raised feature comprising a deformed section of thespring elements.
 5. The contact assembly of claim 1 wherein the contactmembers comprise cantilevered spring elements projecting upwardly intothe opening, and the cantilevered spring elements have a raised featurecomprising a bump of a separate material on the spring elements.
 6. Thecontact assembly of claim 1 wherein the contact members comprisediscrete fingers that are separate from one another and attacheddirectly to the support member.
 7. The contact assembly of claim 1wherein: the support member comprises a conductive support ring and adielectric coating on at least a portion of the support ring; thecontact system further comprises a conductive mounting section attacheddirectly to the support ring; and the contact members are fingersintegral with the mounting section.
 8. The contact assembly of claim 7wherein the mounting section comprises an arcuate element and thefingers project inwardly from the arcuate element along a radius of thesupport ring.
 9. The contact assembly of claim 7 wherein the mountingsection comprises an arcuate element and the fingers project inwardlyfrom the arcuate element along a radius of the support ring, and thefingers have a raised contact feature.
 10. The contact assembly of claim7 wherein the mounting section comprises an arcuate element and thefingers project inwardly from the arcuate element at an angle relativeto a radius of the support ring.
 11. The contact assembly of claim 7wherein the mounting section comprises an arcuate element and thefingers project inwardly from the arcuate element at an angle relativeto a radius of the support ring, and the fingers have a raised contactfeature.
 12. The contact assembly of claim 1 wherein: the contactmembers comprise generally flat, conductive fingers and a platinumcoating directly on the fingers; and the dielectric coating covers atleast a portion of the platinum coating on the fingers such that aregion of the platinum coating is exposed.
 13. The contact assembly ofclaim 1 wherein: the contact members comprise fingers having a raisedfeature at the contact site and a platinum coating on the raisedfeatures; and the dielectric coating covers the fingers adjacent to theraised features such that at least a portion of the platinum coating onthe raised features is exposed.
 14. The contact assembly of claim 1wherein the support member comprises a ring and a plurality of postsdepending from the ring that are separated from one another by gaps. 15.The contact assembly of claim 1 wherein: he support member comprises aring and a plurality of posts depending from the ring that are separatedfrom one another by gaps; and the contact assembly further comprises aconductive mounting section attached directly to the posts to defineflow paths through the gaps and the contact members comprise fingersintegral with the arcuate element that project inwardly into theopening.
 16. The contact assembly of claim 1 wherein: the support membercomprises a ring and a plurality of posts depending from the ring thatare separated from one another by gaps; and the contact assembly furthercomprises a conductive arcuate element attached directly to the posts todefine flow paths through the gaps and the contact members comprisefingers integral with the arcuate element that project inwardly into theopening along a radius of the ring.
 17. The contact assembly of claim 1wherein: the support member comprises a ring and a plurality of postsdepending from the ring that are separated from one another by gaps; andthe contact assembly further comprises a conductive arcuate elementattached directly to the posts to define flow paths through the gaps andthe contact members comprise fingers integral with the arcuate elementthat project inwardly into the opening along a radius of the ring, andwherein the fingers have a raised contact feature.
 18. The contactassembly of claim 1 wherein: the support member comprises a ring and aplurality of posts depending from the ring that are separated from oneanother by gaps; and the contact assembly further comprises a conductivearcuate element attached directly to the posts to define flow pathsthrough the gaps and the contact members comprise fingers integral withthe arcuate element that project inwardly into the opening at an anglerelative to a radius of the ring.
 19. The contact assembly of claim 1wherein: the support member comprises a ring and a plurality of postsdepending from the ring that are separated from one another by gaps; andthe contact assembly further comprises a conductive arcuate elementattached directly to the posts to define flow paths through the gaps andthe contact members comprise fingers integral with the arcuate elementthat project inwardly into the opening at an angle relative to a radiusof the ring, and wherein the fingers have a raised feature.
 20. Acontact assembly for use in an electrochemical deposition system toapply an electrical potential to a microelectronic workpiece, thecontact assembly comprising: a support member having an inner walldefining an opening configured to allow the workpiece to move throughthe support member along an access path; and a contact system coupled tothe support member, the contact system comprising a plurality of contactmembers positioned inwardly into the opening relative to the supportmember to contact a peripheral portion of the workpiece, wherein thecontact members are configured to engage a plating solution during aplating cycle.
 21. The contact assembly of claim 20 wherein the contactmembers comprise cantilevered spring elements projecting upwardly intothe opening, a contact site on each spring element, and a dielectriccoating on the spring elements that is configured to expose the contactsites.
 22. The contact assembly of claim 21 wherein the cantileveredspring elements have a raised feature.
 23. The contact assembly of claim21 wherein the cantilevered spring elements have a raised featurecomprising a deformed section of the spring elements.
 24. The contactassembly of claim 21 wherein the cantilevered spring elements have araised feature comprising a bump of a separate material on the springelements.
 25. The contact assembly of claim 20 wherein: the supportmember comprises a conductive support ring; and the contact systemfurther comprises a conductive mounting section attached directly to thesupport ring, and the contact members are fingers integral with themounting section that each have a contact site configured toelectrically contact the workpiece.
 26. The contact assembly of claim 25wherein the mounting section comprises an arcuate element and thefingers project inwardly from the arcuate element along a radius of thesupport ring, and the fingers have a raised contact feature.
 27. Thecontact assembly of claim 25 wherein the mounting section comprises anarcuate element and the fingers project inwardly from the arcuateelement at an angle relative to a radius of the support ring, and thefingers have a raised contact feature.
 28. The contact assembly of claim20 wherein: the support member comprises a ring and a plurality of postsdepending from the ring that are separated from one another by gaps; thecontact assembly further comprises a conductive arcuate element attacheddirectly to the posts to define flow paths through the gaps and thecontact members comprise fingers integral with the arcuate element thatproject inwardly into the opening; and the support member and thecontact assembly are coated with a dielectric coating that is configuredto expose contact sites on the fingers.
 29. The contact assembly ofclaim 28 wherein the fingers project inwardly into the opening along aradius of the ring and have a raised contact feature.
 30. The contactassembly of claim 28 wherein the fingers project inwardly into theopening at an angle relative to a radius of the ring.
 31. The contactassembly of claim 28 wherein the fingers project inwardly into theopening at an angle relative to a radius of the ring and have a raisedfeature.
 32. A contact assembly for use in an electrochemical depositionsystem to apply an electrical potential to a microelectronic workpiece,the contact assembly comprising: a conductive support member having aninner wall defining an opening configured to allow the workpiece to movethrough the support member along an access path; and a contact systemcomprising an arcuate mounting section coupled to the support member, aplurality of conductive cantilevered spring elements projecting from thearcuate mounting section inwardly into the opening relative to thesupport member and transversely with respect to the access path, adielectric coating covering at least a portion of the spring elements,and electrically conductive contact sites exposed through the dielectriccoating.
 33. A contact assembly for use in an electrochemical depositionsystem to conduct electrical power to a microelectronic workpiece, thecontact assembly comprising: a support member having an inner walldefining an opening configured to allow the workpiece to move throughthe support member along an access path; and a contact system coupled tothe support member, the contact system comprising a plurality of contactmembers positioned inwardly into the opening relative to the supportmember to contact a peripheral portion of the workpiece, wherein thecontact members comprise electrically conductive fingers and raisedcontact sites projecting from the fingers.
 34. The contact assembly ofclaim 33 wherein the raised contact sites comprise a deformed section ofthe fingers.
 35. The contact assembly of claim 33 wherein the raisedcontact sites comprise a bump of a separate material on the fingers. 36.The contact assembly of claim 33 wherein: the support member comprises aring and a plurality of posts depending from the ring that are separatedfrom one another by gaps; and the contact assembly further comprises aconductive arcuate element attached directly to the posts to define flowpaths through the gaps and the fingers are integral with the arcuateelement, wherein the contact assembly is coated with a dielectriccoating configured to expose the raised contact sites.
 37. The contactassembly of claim 36 wherein the fingers project inwardly into theopening along a radius of the ring.
 38. The contact assembly of claim 36wherein the fingers project inwardly into the opening at an anglerelative to a radius of the ring.
 39. A contact assembly for use in anelectrochemical deposition system to conduct electrical power to amicroelectronic workpiece, the contact assembly comprising: a supportmember having a first section and a second section depending from thefirst section, the first section having an inner wall defining anopening configured to allow the workpiece to move through the supportmember along an access path, and the second section being defined by aplurality of posts depending from the first section, wherein the postsare separated from one another by gaps; and a contact system coupled tothe posts of support member, the contact system comprising a pluralityof contact members projecting inwardly into the opening relative to thesupport member to contact a peripheral portion of the workpiece.
 40. Thecontact assembly of claim 39 wherein the contact assembly furthercomprises a conductive arcuate element attached directly to the posts todefine flow paths through the gaps and the contact members comprisefingers integral with the arcuate element that project inwardly into theopening along a radius of the opening.
 41. The contact assembly of claim39 wherein the contact assembly further comprises a conductive arcuateelement attached directly to the posts to define flow paths through thegaps and the contact members comprise fingers integral with the arcuateelement that project inwardly into the opening along a radius of thering, and wherein the fingers have a raised contact feature.
 42. Thecontact assembly of claim 39 wherein the contact assembly furthercomprises a conductive arcuate element attached directly to the posts todefine flow paths through the gaps and the contact members comprisefingers integral with the arcuate element that project inwardly into theopening at an angle relative to a radius of the ring.
 43. The contactassembly of claim 39 wherein the contact assembly further comprises aconductive arcuate element attached directly to the posts to define flowpaths through the gaps and the contact members comprise fingers integralwith the arcuate element that project inwardly into the opening at anangle relative to a radius of the ring, and wherein the fingers have araised feature.
 44. A reactor for electrochemical deposition processingof microelectronic workpieces, comprising: a bowl configured to hold aplating solution; an anode in the bowl at a location to contact theplating solution; a head assembly moveable relative to the bowl betweena first position to load/unload a workpiece and a second position toplace at least a portion of the workpiece in the plating solution; and acontact assembly comprising a support member and a contact system,wherein— the support member has an inner wall defining an openingconfigured to allow the workpiece to move through the support memberalong an access path, and the contact system is coupled to the supportmember, wherein the contact system has a plurality of contact membersprojecting inwardly into the opening relative to the support member andtransversely with respect to the access path, and wherein each contactmember has a contact site configured to electrically contact theworkpiece and a dielectric coating around the contact site.
 45. Thereactor of claim 44 wherein the contact members comprise cantileveredspring elements projecting upwardly into the opening.
 46. The reactor ofclaim 44 wherein the contact members comprise cantilevered springelements projecting upwardly into the opening, and the cantileveredspring elements have a raised feature.
 47. The reactor of claim 44wherein the contact members comprise cantilevered spring elementsprojecting upwardly into the opening, and the cantilevered springelements have a raised feature comprising a deformed section of thespring elements.
 48. The reactor of claim 44 wherein the contact memberscomprise cantilevered spring elements projecting upwardly into theopening, and the cantilevered spring elements have a raised featurecomprising a bump of a separate material on the spring elements.
 49. Thereactor of claim 44 wherein: the support member comprises a ring and aplurality of posts depending from the ring that are separated from oneanother by gaps; and the contact assembly further comprises a conductivearcuate element attached directly to the posts to define flow pathsthrough the gaps and the contact members comprise fingers integral withthe arcuate element that project inwardly into the opening along aradius of the ring.
 50. The reactor of claim 44 wherein: the supportmember comprises a ring and a plurality of posts depending from the ringthat are separated from one another by gaps; and the contact assemblyfurther comprises a conductive arcuate element attached directly to theposts to define flow paths through the gaps and the contact memberscomprise fingers integral with the arcuate element that project inwardlyinto the opening along a radius of the ring, and wherein the fingershave a raised contact feature.
 51. The reactor of claim 44 wherein: thesupport member comprises a ring and a plurality of posts depending fromthe ring that are separated from one another by gaps; and the contactassembly further comprises a conductive arcuate element attacheddirectly to the posts to define flow paths through the gaps and thecontact members comprise fingers integral with the arcuate element thatproject inwardly into the opening at an angle relative to a radius ofthe ring.
 52. The reactor of claim 44 wherein: the support membercomprises a ring and a plurality of posts depending from the ring thatare separated from one another by gaps; and the contact assembly furthercomprises a conductive arcuate element attached directly to the posts todefine flow paths through the gaps and the contact members comprisefingers integral with the arcuate element that project inwardly into theopening at an angle relative to a radius of the ring, and wherein thefingers have a raised feature.
 53. A reactor for electrochemicaldeposition processing of microelectronic workpieces, comprising: a bowlconfigured to hold a plating solution; anode in the bowl at a locationto contact the plating solution; a head assembly moveable relative tothe bowl between a first position to load/unload a workpiece and asecond position to place at least a portion of the workpiece in theplating solution; and a contact assembly comprising a support member anda contact system, wherein— the support member has an inner wall definingan opening configured to allow the workpiece to move through the supportmember along an access path; and the contact system is coupled to thesupport member, wherein the contact system comprises a plurality ofcontact members positioned inwardly into the opening relative to thesupport member to contact a peripheral portion of the workpiece, andwherein the contact members are configured to be immersed in a platingsolution during a plating cycle.
 54. The reactor of claim 53 wherein thecontact members comprise cantilevered spring elements projectingupwardly into the opening, a contact site on the spring elements, and adielectric coating on the spring elements that is configured to exposethat contact sites.
 55. The reactor of claim 54 wherein the cantileveredspring elements have a raised feature.
 56. The reactor of claim 54wherein the cantilevered spring elements have a raised featurecomprising a deformed section of the spring elements.
 57. The reactor ofclaim 54 wherein the cantilevered spring elements have a raised featurecomprising a bump of a separate material on the spring elements.
 58. Thereactor of claim 53 wherein: the support member comprises a conductivesupport ring; and the contact system further comprises a conductivemounting section attached directly to the support ring, the contactmembers are fingers integral with the mounting section, and each fingerhas a contact site configured to electrically contact the workpiece. 59.The reactor of claim 58 wherein the mounting section comprises anarcuate element and the fingers project inwardly from the arcuateelement along a radius of the support ring, and the fingers have araised contact feature at the contact sites.
 60. The reactor of claim 58wherein the mounting section comprises an arcuate element and thefingers project inwardly from the arcuate element at an angle relativeto a radius of the support ring, and the fingers have a raised contactfeature at the contact sites.
 61. The reactor of claim 53 wherein: thesupport member comprises a ring and a plurality of posts depending fromthe ring that are separated from one another by gaps; the contactassembly further comprises a conductive arcuate element attacheddirectly to the posts to define flow paths through the gaps and thecontact members comprise fingers integral with the arcuate element thatproject inwardly into the opening; and the support member and thecontact assembly are coated with a dielectric coating that is configuredto expose contact sites on the fingers.
 62. The reactor of claim 61wherein the fingers project inwardly into the opening along a radius ofthe ring and have a raised contact feature.
 63. The reactor of claim 61wherein the fingers project inwardly into the opening at an anglerelative to a radius of the ring.
 64. The reactor of claim 61 whereinthe fingers project inwardly into the opening at an angle relative to aradius of the ring and have a raised feature.
 65. A reactor forelectrochemical deposition processing of microelectronic workpieces,comprising: a bowl configured to hold a plating solution; an anode inthe bowl at a location to contact the plating solution; a head assemblymoveable relative to the bowl between a first position to load/unload aworkpiece and a second position to place at least a portion of theworkpiece in the plating solution; and a contact assembly comprising aconductive support member and a contact system, wherein— the conductivesupport member has an inner wall defining an opening configured to allowthe workpiece to move through the support member along an access path;and the contact system comprises an arcuate mounting section coupled tothe support member, a plurality of conductive cantilevered springelements projecting from the arcuate mounting section inwardly into theopening relative to the support member and transversely with respect tothe access path, a dielectric coating covering at least a portion of thespring elements, and an electrically conductive contact site on eachspring element exposed through the dielectric coating.
 66. A reactor forelectrochemical deposition processing of microelectronic workpieces,comprising: a bowl configured to hold a plating solution; an anode inthe bowl at a location to contact the plating solution; a head assemblymoveable relative to the bowl between a first position to load/unload aworkpiece and a second position to place at least a portion of theworkpiece in the plating solution; and a contact assembly comprising asupport member and a contact system, wherein— the support member has aninner wall defining an opening configured to allow the workpiece to movethrough the support member along an access path; and the contact systemis coupled to the support member, wherein the contact system comprises aplurality of contact members positioned inwardly into the openingrelative to the support member to contact a peripheral portion of theworkpiece, and wherein the contact members comprise electricallyconductive fingers and raised contact sites projecting from the fingers.67. The reactor of claim 66 wherein the raised contact sites comprise adeformed section of the fingers.
 68. The reactor of claim 66 wherein theraised contact sites comprise a bump of a separate material on thefingers.
 69. The reactor of claim 66 wherein: the support membercomprises a ring and a plurality of posts depending from the ring thatare separated from one another by gaps; and the contact assembly furthercomprises a conductive arcuate element attached directly to the posts todefine flow paths through the gaps and the fingers are integral with thearcuate element, wherein the contact assembly is coated with adielectric coating configured to expose contact sites on the fingers.70. The reactor of claim 66 wherein the fingers project inwardly intothe opening along a radius of the ring.
 71. The reactor of claim 66wherein the fingers project inwardly into the opening at an anglerelative to a radius of the ring.
 72. A reactor for electrochemicaldeposition processing of microelectronic workpieces, comprising: a bowlconfigured to hold a plating solution; an anode in the bowl at alocation to contact the plating solution; a head assembly moveablerelative to the bowl between a first position to load/unload a workpieceand a second position to place at least a portion of the workpiece inthe plating solution; and a contact assembly comprising a support memberand a contact system, wherein— the support member has a first sectionand a second section depending from the first section, the first sectionhaving an inner wall defining an opening configured to allow theworkpiece to move through the support member along an access path, andthe second section being defined by a plurality of posts depending fromthe first section, wherein the posts are separated from one another bygaps; and the contact system is coupled to the posts of support member,wherein the contact system comprises a plurality of contact membersprojecting inwardly into the opening relative to the support member tocontact a peripheral portion of the workpiece.
 73. An apparatus forelectrochemical deposition, comprising: a cabinet; an electroplatingchamber in the cabinet, the electroplating chamber comprising a bowlconfigured to hold a plating solution, an anode in the bowl at alocation to contact the plating solution, a head assembly moveablerelative to the bowl, and a contact assembly comprising a support memberand a contact system, wherein— the support member has an inner walldefining an opening configured to allow the workpiece to move throughthe support member along an access path, and the contact system iscoupled to the support member, wherein the contact system has aplurality of contact members projecting inwardly into the openingrelative to the support member and transversely with respect to theaccess path, and wherein the contact members have a contact siteconfigured to electrically contact the workpiece and a dielectriccoating around the contact site.
 74. An apparatus for electrochemicaldeposition, comprising: a cabinet; an electroplating chamber in thecabinet, the electroplating chamber comprising a bowl configured to holda plating solution, an anode in the bowl at a location to contact theplating solution, a head assembly moveable relative to the bowl, and acontact assembly comprising a support member and a contact system,wherein— the support member has an inner wall defining an openingconfigured to allow the workpiece to move through the support memberalong an access path; and the contact system is coupled to the supportmember, wherein the contact system comprises a plurality of contactmembers positioned inwardly into the opening relative to the supportmember to contact a peripheral portion of the workpiece, and whereineach contact member has a raised feature at a contact site.
 75. Anapparatus for electrochemical deposition, comprising: a cabinet; anelectroplating chamber in the cabinet, the electroplating chambercomprising a bowl configured to hold a plating solution, an anode in thebowl at a location to contact the plating solution, a head assemblymoveable relative to the bowl, and a contact assembly comprising asupport member and a contact system, wherein— the support member has afirst section and a second section depending from the first section, thefirst section having an inner wall defining an opening configured toallow the workpiece to move through the support member along an accesspath, and the second section being defined by a plurality of postsdepending from the first section, wherein the posts are separated fromone another by gaps; and the contact system is coupled to the posts ofsupport member, wherein the contact system comprises a plurality ofcontact members projecting inwardly into the opening relative to thesupport member to contact a peripheral portion of the workpiece.
 76. Amethod for manufacturing a contact assembly for use in anelectrochemical deposition system to apply an electrical potential to amicroelectronic workpiece, the method comprising: coating at least aportion of a contact system with a dielectric coating; and removingsections of the dielectric coating that cover contact sites on contactmembers of the contact system by ablating the dielectric coating with aradiation energy.
 77. The method of claim 77 wherein ablating thedielectric coating comprises impinging a laser against the dielectriccoating over the contact sites.
 78. The method of claim 76 wherein: themethod further comprises plating the contact system with a conductivecontact material before coating the contact system with the dielectriccoating; and ablating the dielectric coating comprises impinging a laseragainst the dielectric coating over the contact sites to expose thecontact material at the contact sites.
 79. The method of claim 76wherein: ablating the dielectric coating comprises impinging a laseragainst the dielectric coating over the contact sites to expose anunderlying material at the contact sites; and the method furthercomprises depositing a conductive contact material onto the exposedunderlying material at the contact sites.